| 154 | // Handle cases where 'this.is_simple()' and unequal to 't'. |
| 155 | // Subclassed xmeet calls can assert that '!t.is_simple()'. |
| 156 | Type xmeet(Type t) { |
| 157 | assert is_simple(); // Should be overridden in subclass |
| 158 | // ANY meet anything is thing; thing meet ALL is ALL |
| 159 | if( _type==TBOT || t._type==TTOP ) return this; |
| 160 | if( _type==TTOP || t._type==TBOT ) return t; |
| 161 | |
| 162 | // RHS TypeNil vs NIL/XNIL |
| 163 | if( _type== TNIL ) return t instanceof TypeNil ptr ? ptr.meet0() : (t._type==TXNIL ? TypePtr.PTR : BOTTOM); |
| 164 | if( _type== TXNIL ) return t instanceof TypeNil ptr ? ptr.meetX() : (t._type== TNIL ? TypePtr.PTR : BOTTOM); |
| 165 | |
| 166 | // 'this' is only {TCTRL,TXCTRL} |
| 167 | // Other non-simple RHS things bottom out |
| 168 | if( !t.is_simple() ) return BOTTOM; |
| 169 | // If RHS is NIL/XNIL |
| 170 | if( t._type==TNIL || t._type==TXNIL ) return BOTTOM; |
| 171 | // Both are {TCTRL,TXCTRL} and unequal to each other |
| 172 | return _type==TCTRL || t._type==TCTRL ? CONTROL : XCONTROL; |
| 173 | } |
| 174 | |
| 175 | public Type dual() { |
| 176 | return switch( _type ) { |